duck-typed object input adapters

include/nlohmann/detail/input/binary_reader.hpp

@@ -31,10 +31,9 @@ namespace detail
 /*!
 @brief deserialization of CBOR, MessagePack, and UBJSON values
 */
-template<typename BasicJsonType, typename SAX = json_sax_dom_parser<BasicJsonType>, typename InputAdapterType = input_adapter_protocol>
+template<typename BasicJsonType, typename InputAdapterType, typename SAX = json_sax_dom_parser<BasicJsonType>>
 class binary_reader
 {
-    using input_adapter_ptr_t = std::shared_ptr<InputAdapterType>;
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
@@ -47,10 +46,9 @@ class binary_reader
 
     @param[in] adapter  input adapter to read from
     */
-    explicit binary_reader(input_adapter_ptr_t adapter) : ia(std::move(adapter))
+    explicit binary_reader(InputAdapterType&& adapter) : ia(std::move(adapter))
     {
         (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
-        assert(ia);
     }
 
     // make class move-only
@@ -1810,7 +1808,7 @@ class binary_reader
     int get()
     {
         ++chars_read;
-        return current = ia->get_character();
+        return current = ia.get_character();
     }
 
     /*!
@@ -1966,7 +1964,7 @@ class binary_reader
 
   private:
     /// input adapter
-    input_adapter_ptr_t ia = nullptr;
+    InputAdapterType ia;
 
     /// the current character
     int current = std::char_traits<char>::eof();

include/nlohmann/detail/input/lexer.hpp

@@ -99,11 +99,9 @@ class lexer_base
 
 This class organizes the lexical analysis during JSON deserialization.
 */
-template<typename BasicJsonType, typename InputAdapterType = input_adapter_protocol>
+template<typename BasicJsonType, typename InputAdapterType>
 class lexer : public lexer_base<BasicJsonType>
 {
-    using input_adapter_ptr_t = std::shared_ptr<InputAdapterType>;
-
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
@@ -112,7 +110,7 @@ class lexer : public lexer_base<BasicJsonType>
   public:
     using token_type = typename lexer_base<BasicJsonType>::token_type;
 
-    explicit lexer(input_adapter_ptr_t&& adapter)
+    explicit lexer(InputAdapterType&& adapter)
         : ia(std::move(adapter)), decimal_point_char(get_decimal_point()) {}
 
     // delete because of pointer members
@@ -1264,7 +1262,7 @@ scan_number_done:
         }
         else
         {
-            current = ia->get_character();
+            current = ia.get_character();
         }
 
         if (JSON_HEDLEY_LIKELY(current != std::char_traits<char>::eof()))
@@ -1488,7 +1486,7 @@ scan_number_done:
 
   private:
     /// input adapter
-    input_adapter_ptr_t ia = nullptr;
+    InputAdapterType ia;
 
     /// the current character
     std::char_traits<char>::int_type current = std::char_traits<char>::eof();

include/nlohmann/detail/input/parser.hpp

@@ -49,10 +49,9 @@ using parser_callback_t =
 
 This class implements a recursive descent parser.
 */
-template<typename BasicJsonType, typename InputAdapterType = input_adapter_protocol>
+template<typename BasicJsonType, typename InputAdapterType>
 class parser
 {
-    using input_adapter_ptr_t = std::shared_ptr<InputAdapterType>;
     using number_integer_t = typename BasicJsonType::number_integer_t;
     using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
     using number_float_t = typename BasicJsonType::number_float_t;
@@ -62,7 +61,7 @@ class parser
 
   public:
     /// a parser reading from an input adapter
-    explicit parser(input_adapter_ptr_t&& adapter,
+    explicit parser(InputAdapterType&& adapter,
                     const parser_callback_t<BasicJsonType> cb = nullptr,
                     const bool allow_exceptions_ = true)
         : callback(cb), m_lexer(std::move(adapter)), allow_exceptions(allow_exceptions_)

include/nlohmann/detail/output/binary_writer.hpp

@@ -1326,7 +1326,7 @@ class binary_writer
 
   private:
     /// whether we can assume little endianess
-    const bool is_little_endian = binary_reader<BasicJsonType>::little_endianess();
+    const bool is_little_endian = binary_reader<BasicJsonType, detail::input_buffer_adapter>::little_endianess();
 
     /// the output
     output_adapter_t<CharType> oa = nullptr;

include/nlohmann/json.hpp

@@ -175,7 +175,7 @@ class basic_json
     friend class ::nlohmann::detail::iter_impl;
     template<typename BasicJsonType, typename CharType>
     friend class ::nlohmann::detail::binary_writer;
-    template<typename BasicJsonType, typename SAX, typename InputType>
+    template<typename BasicJsonType, typename InputType, typename SAX>
     friend class ::nlohmann::detail::binary_reader;
     template<typename BasicJsonType>
     friend class ::nlohmann::detail::json_sax_dom_parser;
@@ -190,7 +190,7 @@ class basic_json
 
     template<typename InputAdapterType>
     static ::nlohmann::detail::parser<basic_json, InputAdapterType> parser(
-        std::shared_ptr<InputAdapterType> adapter,
+        InputAdapterType adapter,
         detail::parser_callback_t<basic_json>cb = nullptr,
         bool allow_exceptions = true
     )
@@ -210,7 +210,8 @@ class basic_json
     template<typename CharType>
     using output_adapter_t = ::nlohmann::detail::output_adapter_t<CharType>;
 
-    using binary_reader = ::nlohmann::detail::binary_reader<basic_json>;
+    template<typename InputType>
+    using binary_reader = ::nlohmann::detail::binary_reader<basic_json, InputType>;
     template<typename CharType> using binary_writer = ::nlohmann::detail::binary_writer<basic_json, CharType>;
 
     using serializer = ::nlohmann::detail::serializer<basic_json>;
@@ -6303,11 +6304,10 @@ class basic_json
     {
         assert(sax);
 
-        auto input_adapter = detail::input_adapter(std::forward<InputType>(i));
-        using adapter_type = typename decltype(input_adapter)::element_type;
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
         return format == input_format_t::json
-               ? parser(std::move(input_adapter)).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, SAX, adapter_type>(std::move(input_adapter)).sax_parse(format, sax, strict);
+               ? parser(std::move(ia)).sax_parse(sax, strict)
+               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia)).sax_parse(format, sax, strict);
     }
 
     template <typename SAX>
@@ -6318,11 +6318,10 @@ class basic_json
     {
         assert(sax);
 
-        auto input_adapter = i.get();
-        using adapter_type = typename decltype(input_adapter)::element_type;
+        auto ia = i.get();
         return format == input_format_t::json
-               ? parser(std::move(input_adapter)).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, SAX, adapter_type>(std::move(input_adapter)).sax_parse(format, sax, strict);
+               ? parser(std::move(ia)).sax_parse(sax, strict)
+               : detail::binary_reader<basic_json, decltype(ia), SAX>(std::move(ia)).sax_parse(format, sax, strict);
     }
 
 
@@ -7026,7 +7025,8 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<InputType>(i))).sax_parse(input_format_t::cbor, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::cbor, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7042,7 +7042,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::cbor, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::cbor, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7053,7 +7053,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(i.get()).sax_parse(input_format_t::cbor, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(i.get()).sax_parse(input_format_t::cbor, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7147,7 +7147,8 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<InputType>(i))).sax_parse(input_format_t::msgpack, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::msgpack, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7163,7 +7164,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::msgpack, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::msgpack, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7175,7 +7176,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(i.get()).sax_parse(input_format_t::msgpack, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(i.get()).sax_parse(input_format_t::msgpack, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7249,7 +7250,8 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<InputType>(i))).sax_parse(input_format_t::ubjson, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::ubjson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7265,7 +7267,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::ubjson, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::ubjson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7276,7 +7278,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(i.get()).sax_parse(input_format_t::ubjson, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(i.get()).sax_parse(input_format_t::ubjson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7349,7 +7351,8 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::input_adapter(std::forward<InputType>(i))).sax_parse(input_format_t::bson, &sdp, strict);
+        auto ia = detail::input_adapter(std::forward<InputType>(i));
+        const bool res = binary_reader<decltype(ia)>(std::move(ia)).sax_parse(input_format_t::bson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7365,7 +7368,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::bson, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(detail::span_input_adapter(std::forward<A1>(a1), std::forward<A2>(a2)).get()).sax_parse(input_format_t::bson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
 
@@ -7376,7 +7379,7 @@ class basic_json
     {
         basic_json result;
         detail::json_sax_dom_parser<basic_json> sdp(result, allow_exceptions);
-        const bool res = binary_reader(i.get()).sax_parse(input_format_t::bson, &sdp, strict);
+        const bool res = binary_reader<detail::input_buffer_adapter>(i.get()).sax_parse(input_format_t::bson, &sdp, strict);
         return res ? result : basic_json(value_t::discarded);
     }
     /// @}

test/src/unit-class_lexer.cpp

@@ -39,9 +39,8 @@ namespace
 // shortcut to scan a string literal
 json::lexer::token_type scan_string(const char* s)
 {
-    auto input_adapter = nlohmann::detail::input_adapter(s);
-    using input_adapter_type = typename decltype(input_adapter)::element_type;
-    return nlohmann::detail::lexer<json, input_adapter_type>(std::move(input_adapter)).scan();
+    auto ia = nlohmann::detail::input_adapter(s);
+    return nlohmann::detail::lexer<json, decltype(ia)>(std::move(ia)).scan();
 }
 }